Challenge 1: Virtual Directory vs. Application -- Solution Walkthrough

The two concrete differences: an application gets its own Application
Pool assignment, independent of whatever pool its parent uses, while
a virtual directory always inherits the parent's pool and never has
an assignment of its own. Second, an application gets its own
isolated .NET AppDomain -- even if it happens to be assigned to the
same Application Pool as its parent -- while a virtual directory
shares its parent's AppDomain entirely, with no isolation at the .NET
runtime level either.

Why converting to an application is the only way to give a folder its
own pool: Application Pool assignment in IIS is a property specifically
of the application object, not of a virtual directory or a plain
subfolder. A virtual directory's configuration schema simply has no
field for "which Application Pool does this run under" -- it isn't a
setting that's merely defaulted to the parent's value and could be
overridden, it doesn't exist as an assignable property at all until
the folder is promoted to an application. That promotion is what adds
the Application Pool assignment as a configurable property in the
first place.

WHY THIS WORKS AS AN ANSWER
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This exercise checks that the reader can name both real differences
(Application Pool assignment and AppDomain isolation) rather than just
one, and understands that the limitation isn't a locked-but-existing
setting -- it's that Application Pool assignment isn't a property a
virtual directory has at all.